NEW YORK/BOSTON - The governors of New York and New Jersey declared a state of emergency on Thursday as a major snowstorm hammered the northeastern United States, causing thousands of flight cancellations and paralyzing road travel.

The first major winter storm of 2014 brought bone-chilling temperatures and high winds from the lower Mississippi Valley to the Atlantic coast, with nearly 2 feet (60 cm) of snow falling in some areas of Massachusetts.

Much of the northeast saw heavy snowfall and plummeting temperatures late on Thursday evening and early on Friday, said Jared Guyer, a meteorologist with the National Weather Service.

"That whole region is blanketed in winter storm warnings, which will continue at least through the morning hours if not beyond," Guyer said.

The storm posed the first major challenge to New York's new mayor, Bill de Blasio. The city's reaction to snowstorms has caused political havoc for mayors for decades.

Transportation officials were to close roads south of Albany and east of New York City, which was expected to see up to 8 inches (20 cm) of snow. A little more than 3 inches (8 cm) had fallen in Central Park early on Friday.

"This is the first of many times I will say please stay indoors. Stay out of your cars. If you don't need to go out, please don't go out," de Blasio said after his first emergency management meeting.

Residents in Boston were also bracing for up to 14 inches (36 cm) of snow by Friday morning and Logan International Airport said that up to a quarter of its scheduled flights had been canceled on Thursday afternoon and evening.

In total, nearly 2,500 U.S. flights were cancelled with another 7,000 delayed. Chicago's O'Hare International and Newark's Liberty International Airport were hit the worst, according to FlightAware, a website that tracks air travel.

More than 1,000 U.S. flights were cancelled and more than 150 were delayed early on Friday.

New York Governor Andrew Cuomo and his New Jersey counterpart Chris Christie both ordered state offices closed on Friday for non-essential employees. New Jersey said public schools would be closed in Hoboken and Jersey City on Friday.

A city worker in Philadelphia was killed after a machine he was using was crushed by a mound of de-icing rock salt, NBC News reported. In Chicago, a man was in critical condition after being pulled out of an icy Lake Michigan by fire fighters.

New York's three major airports were preparing to accommodate stranded travellers whose flights were canceled.

"We have a few hundred cots at each of the airports should you decide to become an overnight guest," said Thomas Bosco, an official with the Port Authority of New York and Jersey, at New York's LaGuardia Airport. The authority also runs Newark and John F. Kennedy International Airport.

Ruben Raskin of San Jose, California, who was in the Boston area visiting his girlfriend, worried that his Friday flight out of Logan could be delayed or cancelled.

"It kind of reminds me why I moved to San Jose after going to college out here," said Raskin, 23.

The "Frozen Fenway" winter carnival, featuring sledding and college ice-hockey at the Boston Red Sox baseball stadium was cancelled for Thursday and Friday.

"Temperatures are expected to plummet tonight and tomorrow with wind chills dropping as low as 25 degrees below zero Fahrenheit (-32 Celsius)," said Massachusetts Governor Deval Patrick. "That is a very dangerous set of circumstances."

Patrick told non-essential state workers to head home at 3 p.m. ET (2000 GMT) as did his counterparts in neighbouring Connecticut.

Forecast snowfall varied widely, with Washington expected to see under an inch (2 cm), Philadelphia and New York 4 to 8 inches (10-20 cm), Hartford 6 to 10 inches (15-25 cm) and Boston 8 to 14 inches (20-36 cm).

Officials in Boston and Providence said schools would be closed on Friday, and in other districts throughout the region, parents were bracing for the possibility their children would be home on Friday.

In Cleveland, Ohio, Chris Behm spent an hour trying to reach the vocational training centre for developmentally disabled people where he works before calling the commute off and urging his 19 employees to stay home.

"It was terrible on all of the roads and there is more weather on its way," Behm said. "It just wasn't worth it to open and possibly kill someone."